In the development direction of the liquid crystal display (LCD) for being lighter, thinner, bigger, some uncontrollable factors in the practical processes result in that there are difference among the physical properties of respective positions of the LCD display panel. Thus, in an area larger than one pixel dot, the uneven brightness phenomenon as showing pure gray scale pictures is so called the mura phenomenon in the industry.
The mura phenomenon has already become the bottle neck restricting the development of LCD. By raising the art level or promoting purity of the row materials, the occurrence probability of the mura phenomenon can be reduced. For the LCD display panel of which the manufacture process is accomplished, the physical properties are determined. For compensating the mura phenomenon produced due to the defect in the LCD manufacture process, the gray scale compensation can be employed to calibrate the brightness of the pixel dot to improve the mura phenomenon.
The gray scale compensation is to change the gray scale value of the pixel to achieve the improvement to the brightness uniformity: namely, the mura condition of the gray scale image is shot by camera, and the normal region and the mura region in the gray scale image are determined, and finally, the gray scale value of the mura region is inversely compensated according to the gray scale value of the normal region, and as showing the pure gray scale pictures, a lower gray scale value is applied to the pixel of which the display brightness is higher, and a higher gray scale value is applied to the pixel of which the display brightness is lower. Then, the brightnesses of the respective pixels after the gray scale compensation are closely consistent to achieve the improvement to the mura phenomenon.
At present, the curved liquid crystal TV has become more and more popular. However, after the panel is bent from the plane state to the curved state, the liquid crystal will appear unpredicted mura cause of being squeezed by the glass bent stress (which newly appears after being bent and not exists as the panel is in the plane state). Therefore, the repair cannot be executed as the panel is in the plane state. Then, after the panel is bent to be curved, the only way of the mura compensation repair is to be executed as the panel is in the curved state.
The mura compensation repair methods in the industry are all based on that the panel is in the plane state. As shown in FIG. 1, the display areas of the panel shot by the camera in the plane state and in the curved state have difference. The plane length b in the curved state is smaller than the plane length a in the plane state. Thus, the present plane mura compensation repair method cannot be directly used to calculate the mura compensation values of the respective region locations as the panel is in the curved state, and a compensation method of mura phenomenon applicable for a curved panel has to be developed.